Abstract: An new and improved developing device for use in an image forming apparatus formed in a unitary structure constructed with a developing chamber disposed adjacent to the rotating electrostatic latent image carrying member, and a toner supply chamber for containing new toner. A developing roller is disposed in the developing chamber, for developing an electrostatic latent image formed on the rotating electrostatic latent image carrying member during operation of the image forming apparatus. An agitating roller is disposed in the developing chamber and adjacent to the developing roller, for charging the new toner as supplied from the toner supply chamber. A toner supply roller is arranged at a toner supply outlet of the toner supply chamber, for supplying the new toner from the toner supply chamber to the developing chamber during operation of the image forming apparatus.